Method of preparing a stable dispersion of an inorganic compound in a lubricating oil



amass Patented Dec. 12, 1961 This invention relates to stableoil-dispersible, highly basic, metal-containing, ultra-fine compositionsand methods of making the same. More particularly, this inventionrelates to ultra-fine dispersions of basically reactive inorganiccompounds as alkaline reserve agents for use in lubricating andcorrosion inhibiting compositions and is a continuation, in part, of myco-pending application, Serial No. 547,846, filed November 18, 1955, andnow abandoned.

It is believed that in heavy duty detergent type lubrieating oilcompositions for use in diesel and like internal combustion engines, atleast two requirements must be met by such oils (in addition tolubricity, stability, and the like) if a high degree of enginecleanliness is to be maintained. First, the oil must possess the powerto disperse insolubles formed by fuel combustion or oil oxidation, orboth, and secondly, the oil must be capable of neutralizing acidiclacquer precursors formed by either oil oxidation or interaction of theoil with sulfur acids produced from fuel combustion or both of theseconditions. The detergents generally employed in oils for engineoperation in high sulfur fuels (e.g., conventional metal sulfonates orphenates) are only mildly alkaline and their basicity is rapidlydepleted during engine operation. Various methods have been proposed forthe preparation of overbased metal sulfonates or phenates byincorporating therein various types of metal derivatives or organiccompounds. While the addition of such compounds does increase thebasicity of the resulting composition, the resulting compositionexhibits certain disadvantages. One such disadvantage is that unlessspecial precautions are employed, the diameter of the individualparticles will be greater than desired. Small particles are desirablebecause the smaller the particle the greater will be the surface areaavailable per unit weight for reaction with the acidic materialspresent. Also, if the diameter of the individual particles is too great,the composition will cause abrasion of the metal parts.

It is, therefore, a principal object of the present invention to providea process which will obviate the disadvantages of the prior artprocesses. It is another object of my invention to providemetal-containing stable dispersions of inorganic compounds in mineraloil and process for the production of such dispersions. It is anotherobject of my invention to provide highly useful mineral oil compositionsutilizing such dispersions. Other objects of the invention will appearas the description proceeds.

To the accomplishment of the foregoing and related ends, this inventionthen comprises the features herein after fully described andparticularly pointed out in the claims, the following descriptionsetting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variousways in which the principle of the invention may be employed.

Broadly stated, the present. invention comprises the process ofproducing a stable dispersion of an inorganic material in lubricatingoil which comprises:

A. Forming an emulsion comprising (1) A lubricating oil, (2) A sulfonicacid which upon neutralization produces an oil-soluble salt,

(3) An aqueous solution of a water-soluble inorganic basic compound,

B. Passing an acid gas such as carbon dioxide, or sulfur dioxide,through said emulsion, thereby converting the inorganic basic compoundto a substantially waterinsoluble compound, the individual particles ofwhich are less than 1 micron in diameter, and then C. Removing thewater.

fer to dilute the lubricating oil with a volatile hydro-.

carbon and if that procedure is followed, the volatile hydrocarbon willbe removed with the water in step C above.

Step C of the above described process, removing the water, could beperformed by one of several alternative procedures. Thus, the watercould be removed by subjecting the mixture to distillation either atatmospheric or subatmospheric pressure or the water could be removed byfirst mechanically separating as, for example, by decantation,siphoning, centrifugation, or drawing off a lower layer and thendistillation to remove traces of water and other solvents.

Before proceeding with the specific examples illustrating my invention,it may be well tov indicate in general the types of compounds requiredin the process.

LUBRICATING OIL Suitable lubricating oils are mineral lubricating oilsobtained by any of the conventional refining procedures and syntheticoils such as alkylene polymers as, for example, polymers of propylene,polyoxyalkylene, esters of polyoxypropylene, and dicarboxylic acidesters. Generally, it is desirable although not imperative to dilute thelubricating oil with a volatile hydrocarbon solvent, such as petroleumnaphtha, or other hydrocarbons, such as hexane, heptane, octane,benzene, toluene, or xylene.

SULFONIC ACID Suitable sulfonic acids are those which uponneutralization produce oil-soluble salts and include alkyl sulfonicacids, the so-called mahogany sulfonic acids, petroleum sulfonic acids,and the like. The industrial production of sulfonic acids from petroleumis well understood in the art and is described in the literature.Particularly useful sulfonic acids include diwaxbenzene sulfonic acid,diwaxtoluene sulfonic acid, and postdodecylbenzene sulfonic acid. Thewax in making the wax aromatic sulfonic acid is obtained from differentsources of crude petroleum oil. Various grades of parafiin wax are madewith different melting points. A 119 to 122 F. melting point wax is amixture of organic compounds wherein the molecular weight varies fromabout 330 to 340. The average carbon atom content of this mixture oforganic compounds will be around 24. As the carbon atom content of thewax decreases, the melting point of the wax also decreases. Othersulfonic acids which may be used in the process of this inventioninclude, for example, monoand poly-wax substituted naphthalene sulfonicacid, diphenyl ether sulfonic acid, naphthalene disulfide'sulfonic acid,diphenyl amine sulfonic acid, dicetyl thianthrene sulfonic acid,dilauryl betanaphthol sulfonic acid, dicap-ryl nitronaphthalene sulfonicacid, unsaturated parafiin wax sulfonic acid, hydroxy substitutedparafiin wax sulfonic acid, tetra-amylene sulfonic acid, monoandpoly-chloro-substituted paraffin wax sulfonic acids, nitrosoparafiin waxsulfonic acids, cycloaliphatic sulfonic acids, such as laurylcyclohexylsulfonic acids,

sulfuric acid, oleum, chlorosulfonic acid, etc.

monoand poly-wax substituted cyclohexyl sulfonic acids, and the like.Alternately but less preferably, I may use the corresponding sulfonatesalts instead of the sulfonic acids.

A particularly useful sulfonic acid is that prepared by sulfonatingpostdodecylbenzene by any of the conventional methods of sulfonatingalkaryl hydrocarbons such as by the treatment of a hydrocarbon withconcentrated Postdodecylbenzene comprises monoalkylbenzenes anddialkylbenzenes in the approximate ratio of 2:3. Its typical physicalproperties are as follows.

Specific gravity at 38 C 0.8649

INORGANIC COMPOUND Suitable inorganic basic compounds for use in myinvention are restricted to those compounds which are water-soluble andwhich upon treatment with the acid gas are rendered substantially waterinsoluble. Typical inorganic basic compounds which may be used are theoxides and hydroxides of the alkali and alkaline earth metals. Specificexamples of suitable basic inorganic compounds include the oxides andhydroxides of barium, lithium, and strontium. Although any'of theforegoing compounds may be-used, I prefer to employ either barium oxideor barium hydroxide.

As to the amount of each of the reactants, suitable and preferredquantities on a weight basis are as follows:

Suitable Preferred (Percent) (Percent) Lubricating oil 5-25 10-20Volatile hydrocarbon. 0-60 20-40 Sulionic acid 5-25 10-20 Inorganice0rnpound 0. 5-25 5-15 Water 10-60 10-40 The materials are admixed inany suitable reaction vessel, preferably fitted with means for agitationand heated within a temperature range of about 60 to 150 C After mixingto form the dispersion, the acid gas is bubbled through the mixture torender the inorganic compound water-insoluble. After the reaction iscompleted, the temperature is gradually raised to the point at which thesolvents are removed by distillation. If desired, the product may becentrifuged or filtered in order to produce a bright product but suchtreatment is usually In order to disclose the nature of the presentinvention still more clearly, the following illustrative examples willbe given. It is to be understood that the invention is not to be limitedto the specific conditions or details set forth in these examples exceptinsofar as such limitations are specified in the appended claims. Partsgiven are parts by weight. The barium hydroxide used in the examplescorrespond to the formula Ba(OH) .8I-I O.

Example 1 An aqueous solution of barium oxide was prepared by dissolving44 parts of barium oxide in 200 parts of water. This solution was thenadded to 300 parts of a postdodecylbenzene sulfonic acid solution (0.56meq./ g. 24.3% acid, 24.3% white oil, and 51.4% naphtha) in a reactionvessel provided with means for heating and agitation. Heat was appliedwith agitation until the temperatureof the contents reached 90 C. Carbondioxide was then blown through the mixture until the mixture was acidicto alpha-naphthol benzein indicator. Upon completion of the reaction,the mixture was heated to 150 C. to remove the solvents. After removingthe solvents and centrifuging, the product was bright and had a basenumber of 72.

Example 2 The procedure of, Example 1 was repeated except 16 parts ofsodium postdodecylbenzene sulfonate were added to the 300 parts ofsulfonic acid prior to the addition of the aqueous barium hydroxidesolution thereto. The base number of the final product was 69.

Example 3 An aqueous solution of barium hydroxide was prepared bydissolving 70 parts of barium hydroxide in 200 parts of water. Thissolution was then added to 300 parts of postdodecylbenzene sulfonic acidsolution (0.56 meq./g. 24.3% acid, 24.3% white oil, and 51.4% naphthat)in a reaction vessel provided with means for heating and agitation. Heatwas applied with agitation until the temperature of the contents reachedC. Carbon dioxide was then blown through the mixture until the mixturewas acidic to alpha-naphthol benzein indicator. Upon completion of thereaction, the mixture was heated to 150 C. to remove the solvents. Afterremoving the solvents and centrifuging, the product was bright and had abase number of 70.

' Example 4 The procedure of Example 3 was repeated except 78 parts ofsodium postdodecylbenzene sulfonate were added to the 300 parts ofsulfonic acid prior to the addition of the aqueous barium hydroxidesolution thereto.

Example 5 number of the final product was 88 and it analyzed 19.7

percent barium.

Example 6 The procedure of Example 3 was again repeated with theexception that 90 parts of barium hydroxide was dissolved in 250 partsof water instead of 70 parts of barium hydroxide dissolved in 200 partsof water. The base number of the product was 85.

Example 7 An aqueous solution of barium hydroxide was prepared bydissolving 67 parts of barium hydroxide in 300 parts of water. Thissolution was then added to 300 parts of a postdodecylbenzene sulfonicacid solution (.46 meq./g., 17.3% acid, 17.3% white oil, and 65.4%benzene) in a reaction vessel: provided with means for heat- An aqueoussolution of barium hydroxide was prepared by dissolving 96 parts ofbarium hydroxide in 400 parts of water. This solution was then added toa solution consisting of 400 parts of a 30% active bariumpostdodecylbenzene sulfonate (3.9% barium, .8% sodium) and 100 partsnaphtha in a reaction vessel provided with means for heating andagitation. Heat was applied with agitation until the temperature of thecontents reached 80 C. Carbon dioxide was then blown through the mixtureuntil the mixture was acidic to alpha-naphthol benzein indicator. Uponcompletion of the reaction the mixture was heated to 150 C. to removethe solvents. After removing the solvents and centrifuging, the productwas bright and had a base number of 46.

Example 9 An aqueous solution of barium hydroxide was prepared bydissolving 78 parts of barium hydroxide in 400 parts of water. Thissolution was then added to 300 parts of a postdodecylbenzene sulfonicacid solution (.543 meq./ g., 23.6% acid, 23.6% White oil, and 52.8%naphtha) in a reaction vessel provided with means for heating andagitation. Heat was applied with agitation and the temperature of thecontents was maintained at 100 C. for a period of 2 hours, after whichthe contents were blown with carbon dioxide at the same temperatureuntil the mixture was acidic to alpha-naphthol benzein indicator. Themixture was then heated to 150 C. to remove the solvents. After removingthe solvents and filtering, the product was bright and had a base numberof 74.

Example 10 The procedure of Example 9 was repeated with the exceptionthat 60 parts of barium hydroxide was dissolved in 300 parts of water,the contents were maintained at a temperature of 64 C. for a period of 2hours and was blown with carbon dioxide at a temperature of 95 C. Thefinal product had a base number of 70.

Example 11 contents were blown with carbon dioxide at that temperatureuntil the mixture was acidic to alpha-naphthol benzein indicator. Afterremoving the solventsand filtering, the product was bright and had abase'number of 66.

Example 12 The procedure of Example 11 was followed with the exceptionthat the 60 parts of barium hydroxide were dissolved in 100 parts ratherthan in 250 parts of water. The final product had a base number of 66.

Example 13 An aqueous solution of barium hydroxide was prepared bydissolving 45 parts of barium hydroxide in 250 parts water. Thissolution was then added to 300 parts postdodecylbenzene sulfonic acidsolution (0.54 meq./ g., 23.6% acid, 23.6% white oil, and 52.8% naphtha)in a reaction vessel provided with means for heating and agitation. Heatwas applied with agitation and the contents maintained at 80 C. for twohours, then blown with sulfur dioxide for one hour. Then the contentswere heated to about C., an equal volume of benzene was added, and theremainder of the water removed by azeotropic distillation. The benzenesolution of the product was centrifuged and the benzene was then removedby heating to C. A bright product was obtained which contained 10.3%barium, 4.2% sulfur, and about 5% dispersed BaSO Example 14 An aqueoussolution of barium hydroxide Was pre pared by dissolving 52 parts bariumhydroxide in 250 parts water. This solution was then added to 300 partspostdodecylbenzene sulfonic acid (0.614 meq./g., 25.4% acid, 25.4% whiteoil, and 49.2% naphtha) in a reaction vessel provided with means forheating and agitation. 'I-Ieat was applied with agitation and thecontents maintained at 80 C., for two hours, then blown with carbondioxide until acidic to alpha-naphthyl benzein indicator. The productwas then heated to C., to remove solvent and water, and then filtered. Abright fluid product was obtained which had a base number of 31.

Example 15 An aqueous solution of barium hydroxide was prepared bydissolving 53 parts of Ba(OH) .8H O in 83 parts of Water. This solutionwas then added to 300 parts of the sulfonic acid prepared by sulfonatingpentadecylbenzene bottoms (0.452 meq./g., 21.9% acid, 56.2% toluene, and21.9% white oil) in a reaction vessel provided with means for heatingand agitation. Heat was applied with agitation and the contentsmaintained at reflux (85 C.) for one hour, then blown with carbondioxide until the mixture was acid to alpha-naphtholbenzein indicator.The product was allowed to settle overnight at 70 C. and the aqueouslayer then drawn off from the organic layer. The organic layer was thenheated to 180 C. to remove traces of water and toluene and filtered. Abright fluid product was obtained which had a base number of 67.

While particular embodiments of the invention have been described, itwill be understood, of course, that the invention is not limited theretosince many modifica tions may be made, and it is, therefore,contemplated to cover by the appended claims any such modifications asfall within the true spirit and scope of the invention.

The invention having thus been described, what is claimed and desired tobe secured by Letters Patent is:

1. The process of producing metal-containing, highly basic, stabledispersions of inorganic compounds in lubricating oil compositions whichcomprises:

A. forming an emulsion by agitation and heat within a a temperaturerange of 60 to 150 C., a mixture consisting of a weight basisessentially of:

(1) 5 to 25% of a lubricating oil selected from the group consisting ofmineral and synthetic oils (2) 5 to 25 of a sulfonic acid which uponneutralization produces an oil-soluble salt (3) an aqueous solution ofan inorganic basic compound selected from the group consisting of bariumoxide and barium hydroxides, said solution being characterized furtherin that the amount of water varies from 10 to 60% and the amount of saidinorganic basic compound dissolved in said water varies from 0.5 to 25%of-the total emulsion composition.

(4) 20 to 40% of a volatile hydrocarbon B. passing carbon dioxidethrough said emulsion until C. removing the water and any volatilehydrocarbon. 5

2. The process of ciairn 1 wherein the inorganic basic compound isbarium oxide.

3. The process of claim 1 wherein the inorganic basic compound is bariumhydroxide.

4. The process of claim 1 wherein the sulfonic acid is 1postdodecyibenzene sulfonic acid.

References Cited in the file of this patent UNITED STATES PATENTSMcLcnnan Mar. 18, 1947 Mertes Mar. 28, 1950 Mertes Mar. 28, 1950 MertesDec. 23, 1952 Asseff Nov. 30, 1954 Asseff Nov. 8, 1955 Warren et a1 June17, 1958 Anderson et a1. Dec. 1, 1959

1. THE PROCESS OF PRODUCING METAL-CONTAINING, HIGHLY BASIC, STABLEDISPERSIONS OF INORGANIC COMPOUNDS IN LUBRICATING OIL COMPOSITIONS WHICHCOMPRISES: A. FORMING AN EMULSION BY AGITATION AND HEAT WITHIN ATEMPERATURE RANGE OF 60 TO 150*C., A MIXTURE CONSISTING OF A WEIGHTBASIS ESSENTIALLY OF: (1) 5 TO 25% OF A LUBRICATING OIL SELECTED FROMTHE GROUP CONSISTING OF MINERAL AND SYNTHETIC OILS (2) 5 TO 25% OF ASULFONIC ACID WHICH UPON NEUTRALIZATION PRODUCES AN OIL-SOLUBLE SALT (3)AN AQUEOUS SOLUTION OF AN INORGANIC BASIC COMPOUND SELECTED FROM THEGROUP CONSISTING OF BARIUM OXIDE AND BARIUM HYDROXIDES, SAID SOLUTIONBEING CHARACTERIZED FURTHER IN THAT THE AMOUNT OF WATER VARIES FROM 10TO 60% AND THE AMOUNT OF SAID INORGANIC BASIC COMPOUND DISSOLVED IN SAIDWATER VARIES FROM 0.5 TO 25% OF THE TOTAL EMULSION COMPOSITION. (4) 20TO 40% OF A VOLATILE HYDROCARBON B. PASSING CARBON DIOXIDE THROUGH SAIDEMULSION UNTIL THE SAME IS ACID TO ALPHA-NAPHTHOLBENZEIN INDICATOR,WHEREBY SAID INORGANIC BASIC COMPOUND IS CONVERTED TO WATER-INSOLUBLEPARTICLES HAVING DIAMETERS LESS THAN 1 MICRON, C. REMOVING THE WATER ANDANY VOLATILE HYDROCARBON.